SC900 Radio/Head unit laser cleaning.

[scot850]

There are articles out there on how to clean a Volvo SC-901 radio/ Head unit laser and I assumed that a SC-900 (previous generation) that looks similar would be the same. The cleaning of a SC-901 unit can be found here and has good pictures:

http://volvoforums.com/forum/volvo-c70- ... ror-71226/

Opening the SC-900 unit I discovered it was not the same. I could not get to the laser head as the 3 disc cd cassette was still in place and although I could carefully pull it out on it's sliders I could not get it out far enough to get to the release latch (assuming there is one like on the SC-901). I had to swap it out with my current unit, connect up and power up and enter the code to eject the cd cassette.

I then disconnected the unit again, and opened it up allowing access to the laser to clean it.

Volvo SC-900 Radio/Head unit

Volvo SC-900 head unit. SC-901 looks identical from the front.
To clean the laser you have to remove the top cover by removing the 2 retaining crosshead screws at the back top of the unit. The screwdriver tip is pointing to one of the 2 holes.

Top cover screws removed

Having removed the 2 screws, you need to carefully prise the top off from the back top edge. Be careful as they can be really tight to remove. I used a flat screwdriver so I didn’t cut a finger or chip a nail! Also, you have to only raise it at the rear as you have to lift the top of with rear raised to allow the 3 retaining dimples to clear their slots in the top of the front plastic cover. Not doing so can damage the front plastic face plate.

3 dimples locked in place on face plate

3 dimples in their slots.

Raising top cover from rear of unit

Raising the lid from the back to allow the 3 dimples to clear their slots.

Lid placed back down to show the 3 dimples

Lid placed back down so you can see the 3 dimples clearly.
Next, to access the laser, you need to slide the cd cassette drawer as far forward as possible raising the spindle unit for the cd’s on its’ plate to see the laser head for cleaning.

Push on metal plate below finger with spring on it forward

Use a finger to start sliding the cd cassette tray out. Gently push on the piece of metal with the spring attached until the drawer has started moving, and then gently grip the drawer from the front and slide it out as far as it will go.

CD slide fully out

Drawer as far out as it goes. This will raise the cd spindle unit so you can access the laser head to clean it.

CD spindle assembly raised up

Now you will be able to see the laser head when viewed from the rear of the unit when looking past the spindle head. It is the shiny glass looking item to the left of the picture.

Laser head to left

Clean with some rubbing alcohol and a cotton bud/Q tip. Rub gently!!
I also cleaned the rubber covered spindle that pulls the cd discs into the unit. These are accessed through the same hole. The spindle is slightly longer than a cd is wide. Again gently rub with a cotton bud and rubbing alcohol, and use the tip to rotate the rubber coated spindle.

CD spindles to pull cd in/out of cassette

CD spindle to pull cd in/out of cassette (2)

Viewed from front of unit.

You can then slide the cd drawer back in to close it.

Replacing the top is as you removed it by fitting the lid in to under the front edge of the front plastic cover to allow the 3 dimples to fit into their slots and then lower the back edge down until it snaps shut and refit the 2 crosshead screws.

You can also take the opportunity to clean the 2 drive wheels on the cassette unit and the play head. Lay the unit on its’ RH side (viewed from front) and carefully push the door open with a finger. Use good lighting so you can see what needs to be cleaned. Use 2 cotton buds taped together (as shown in the laser cleaning for the SC-901 unit) to give the length needed to reach the rear drive rubber wheel and the play head.

Unit is then ready to go unless you want to clean the front face. You can use cotton buds dipped in rubbing alcohol, to rub grime of the front and the buttons. DO NOT USE Acetone as it will remove the decals on the front (don’t ask how I know!!).

You can then pop the unit in again to check it all works. Should also have mentioned at the start, when removing the cd cassette, to switch the car lights on to make sure all the buttons light up. That way when you have the unit out you can replace any blown bulbs. I am not covering that as none of my units have any bulbs out. That is for another day!!

Hope this is of use ‘How-to..’ is of help as it will help with poor cd cassette loading issues and possible sticking discs due to dirty rubber rollers.

Hadn’t planned to clean/fix this unit. I was going to take it apart to rob the face-plate and the spring for the cd cassette flap, and to improve my spare SC-901 which is supposed to be a better design. But having found this unit works as intended and is in great shape cosmetically, getting the security code ok, it seems a shame to scrap a perfectly good unit. So I guess it will now have to be sold along with 2 cd cassettes I have for it.

Neil.